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author | Richard Eisenberg <rae@richarde.dev> | 2021-01-05 22:40:53 -0500 |
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committer | Richard Eisenberg <rae@richarde.dev> | 2021-01-15 23:14:13 -0500 |
commit | 7d550ff71ee06c681756f60fbd3731559484afa3 (patch) | |
tree | eab8a083e327c06272f1c95833174ecf347bea45 /compiler/GHC/Core/Lint.hs | |
parent | 0dba78410887ffc3d219639081e284ef7b67560a (diff) | |
download | haskell-wip/T19106.tar.gz |
Make matchableGivens more reliably correct.wip/T19106
This has two fixes:
1. Take TyVarTvs into account in matchableGivens. This
fixes #19106.
2. Don't allow unifying alpha ~ Maybe alpha. This fixes
#19107.
This patch also removes a redundant Note and redirects
references to a better replacement.
Also some refactoring/improvements around the BindFun
in the pure unifier, which now can take the RHS type
into account.
Close #19106.
Close #19107.
Test case: partial-sigs/should_compile/T19106,
typecheck/should_compile/T19107
Diffstat (limited to 'compiler/GHC/Core/Lint.hs')
-rw-r--r-- | compiler/GHC/Core/Lint.hs | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/compiler/GHC/Core/Lint.hs b/compiler/GHC/Core/Lint.hs index 6dc84b91ab..e7be00096a 100644 --- a/compiler/GHC/Core/Lint.hs +++ b/compiler/GHC/Core/Lint.hs @@ -2472,7 +2472,7 @@ compatible_branches (CoAxBranch { cab_tvs = tvs1 lhs2' = substTys subst lhs2 rhs2' = substTy subst rhs2 in - case tcUnifyTys (const BindMe) lhs1 lhs2' of + case tcUnifyTys alwaysBindFun lhs1 lhs2' of Just unifying_subst -> substTy unifying_subst rhs1 `eqType` substTy unifying_subst rhs2' Nothing -> True |